Hydraulic remote control system



Aug. 11, 1942. I I o. A. WHEELQN I 2,292,916 7 I HYDRAULIC REMOTE CONTROL-SYSTEM 7 Filed May 16, 1939 2 Sheets-Sheet 2 BY /5 M I ATTORNEY vibration or external loads.

Patented Aug. 1 1, 1 942 I I UNITED STATES PATENT oF FmE 7 2,292,916 HYDRAULIC REMOTE CONTROL sys'rem Orville A. Wheelon, Pacific Palisades, Calit, assignor to Douglas Aircraft Company, Incorporated, Santa Monica, Calif.

Application May is, 1939, Serial No. 213,959 8 Claims. (01. 60-545) Myinvention relates to a system for actuating an element which is remotely located from the controlling means and has particular reference to a remote control system which is hydrauli insofar as movement from the actuated element is concerned and is therefore not influenced by Also, a positive position indicating means is aiforded for the element being actuated in that the movements of thecontrol and the element correspond as in a manually operated system.

as a rule, been lackingin simple direct position indicating means, andmanually operated closed systems have chiefly obtained irreversibility in the control units by excessive friction or braking means not altogether desirable, especially in the event that it is desired to operate a single element from a plurality of control stations; In such an event it would be common practice to set the braking device on the control last operated in order to obtain irreversibility and prevent the controlled element from being actuated by vibration, etc. However, setting the friction or braking device on one control station would also tend to make' operation from other stations either impossible or very difiicult. Other manually operated closed systems include hand operable pumps with appropriate selectors and electrical position indicators which tend to depart from simplicity of design and operation.

The principal object of the invention is to provide a hydraulic remote control system which may be operated either "manually or by pressure from any one of a plurality of control units, and which is irreversible from the operating unit without impairing ease of operation from any of units.

ment of my control system wherein a single operating unit is adapted'to be actuated by a plurality of control units.

Figure 2 is a cross sectional side elevation of the operating unit showing a piston adapted to reciprocate; and

Figure 3 is a cross sectional side elevation of one of the control units showing, in addition to other details, spring loaded poppet valves and a piston to which a control handle is pivotally connected.

Figure 4 is a schematic diagram of another embodiment-of my control system wherein the control unit'is identical to that of Figure 3, and the operating unit is identical in design but is double the size of the unit of Figure 2; the fluid lines being rearranged with respect to the units. While the invention pertains particularly to an operating unit and a control unit, I have shown in Figures 1 and 4, complete hydraulic systems for the purpose of more clearly describing the After understanding the invention, it will be obvious that numerous embodiments are possible wherein the units may be employed with varying results depending largely upon system arrangements.

In the system of Figure 1, a power supply 4 is .utilized to drive a pump 6 having a suction port 8 and a pressure; port [0. The pump draws fluid from a reservoir I! through aline l4 and discharges the fluid under pressure from port I0 into a line 16. From line It, branch linesl8 been shown, it is obvious that only one, or more than two may be used as necessary to suit par-- ticular installation requirements. Likewise,

more than one operating unit may also be included in the system if desired. When using a plurality of control units and a plurality of operating units, the'control units are connected totrol handles may control a single operating unit.

Other and further objects will become apparent-asthe description proceeds.

Referringnow to the drawings: Figure 1 is a schematic diagram of an embodigether in series while the operating units are connected in parallel- A pressure tank 28,- as disclosed in the copending application No. 262,958 of Harold W.

Adams and Earl S. Kleinhans is connected into line I6 for the purpose of preventing pressure fluctuations or surges from afiecting the smooth operation of the units. Also, a check valve 30 is provided in line 16 just ahead of the control units for retaining fluid in these units and in one side of the operating unit in the event of leakage in the fluid supply portion of the system. This valve also serves to maintain irreversibility I check valve 32 is located in line I8 cation. A floating piston type double acting and is designed to retain fluid in the other side of the operating unit 24, which is unprotected'by the valve 30, and at the same time allow complete operation of the unit in a closed system in the event of leakage or failure anywhere in the system other than inthe units proper or in a line 34 interconnecting the units 26-26 or in a line 36 interconnecting one of the units 26 and the unit 24. Both the design and the operation of the valve 32 will be later described.

A line 38 and a line the fluid from the units 26 to the reservoir I2 piston chamber and port 96 connects the control pressure line 46 into the right end of a poppet valve chamber I06 in the upper left side of the control unit. Port 98 connects the supply pressure line into the left end of the poppet valve chamber I06. Port I00 connects the control pressure line 34, extending form the second control unit into a first mentioned control unit or, if only one unit is installed in the system, the port I00 may be I interconnected with the ports 96-94.

40 are provided to return via a line 42 into which they are connected.

Lines 44-46-48-50-5254-56 interconnect the units 26-26 and may be termed control pressure lines in that they convey pressure fluid only when the control units 26-26 are operated.

Referring now to Figure 2, the operating unit 24 comprises a housing 58 having a cylindrical bore 60 in which reciprocates a piston rod 62 including a piston head 64 on the left end thereof. The head incorporates packings 66 for preventing fluid leakage from one side of said head to the other. The right end 68 of the piston rod extends from the housing 58 and is fluid sealed by a packing 10 held in place by a packing nut 12 threaded into the housing at "and equipped with a dust seal I6.

The bore 60 is ported at 18 to'permit pressure fluid from line I8 to enter the bore on the right side of the piston'head piston rod 62 is sufliciently large to restrict the displacement area of the piston head, upon which the pressure may at, to approximately one-half the displacement area upon may act on the left side of the head. Pressure fluid from line 36 enters the bore 60 on the left side of the piston head by way of a port 80.

Although, as previously mentioned, the control system may be utilized to actuate any desired ,elementwithin reasonable limits, for purposes of description it is here assumed that the element is a throttle of an internal combustion engine. A three-armed bellcrank 82 is pivotally connected at one arm to the .piston rod end 68 and at another arm to a throttle lever 84. Since in some installations it is desirable, in event of throttle control failure, to have the throttle remain in or be moved to the open position, a spring 66 may be attached to the third arm of the bellcrank in a manner such that the tension of the spring will move the control to the desired position in such an emergency. This spring is easily overcome by the fluid pressure in the control system under normal operating conditions but is of sufflcient strength to move the piston if opposing pressureis absent.

With reference 26 comprises a body 88 having a plurality of ports 0662'-6496-98I00. Port 90 connects the line 36 from the operating unit into a piston chamber I02 in the lower right side of the control unit, and port 92 connects the return line 60 into the left end of a poppet valve chamber I04 in the upper right side of the control unit. Port 04 connects the control pressure line 44 into the right end of the poppet valve chamber I04,

to Figure 3, the control unit.

' the fluid is moving. A fluid passage .example, if the fluid and, consequently,

A piston H0 is provided with piston heads II2-I l4 at opposite ends thereof which are adapted to reciprocate'in the chambers I02-I08 respectively. Each piston head is sealed against fluid leakage by packings H6 and incorporates a spring loaded poppet valve assembly II8, the valve of which is unseated by a stem I20 as the piston moves to the end of its stroke in either direction, the stem coming in contact with and being depressed by the end wall of the piston chamber. The valves are also unseated by pressure fluid depending upon the direction in which I22 interconnects the two valve assemblies and allows an interflow of fluid from one piston chamber to the other when both valves are unseated. For

the piston are moving to the right, pressure unseats the valve in piston head II4 allowing fluid to flow through passage I22 until it reaches the valve in piston head II2. This valve checks the flow until the piston has reached the end of its rightward travel and the valve stem I20 is depressed port I00 through the passage 64. The diameter of the by the end wall of the valve is.unseated. Fluid then may flow from I22 to port 90 until theleft end of the operating unit bore 60 is filled, with the piston 64 moved to the extreme right end of its travel. It may be seen that with the piston chamber I02, the line 36, and the left end of the operating unit piston bore 60 filled with which the pressure filled between the control unit and operating However, the metering valve and.

unit pistons. fluld passage arrangement is provided for the purpose of correcting any volume variations resulting from temperature changes in that suillcient fluid will be metered through the control unit piston each time a full stroke is executed to maintain a normal pressure acting on the operating unit piston and automatically synchronize all units.

Acontrol lever I24 for releasing pressure to operatethe piston H0 is pivotally connected to the piston at I26 and extends upwardly through an opening I28 in the control This lever has a cam I30 above the pivotal connection to the piston and m the horizontal plane of the poppet valve chambers I04-I06, and the cam is adapted to contact and displace either of two valve stems I22-I34 depending upon the direction in which the lever is moved. Each valve stem, as it is displaced, unseats its respective spring loaded ball I36 and permits fluid flow from one side of the valve to the other. For inmoved counterclockwise about its pivotal connection I26, the cam I30 contacts and displaces the stem I 34 which.in

turn unseats its respective ball valve I36. This I08 in the lower left side of the piston chamber I02 whereupon unit housing 86.

allows pressure fluid to flow from the constant pressure line 20, through the port 98, past the ball valve and into the control pressure line 48 via port 96. Assuming now that only one controlunit is in the system and the ports 96 and I are interconnected, the pressure fluid enters the piston chamber I08 and moves the piston to the right and, as forceis being applied to the lever at I38 by the operator, the axis of lever rotation is then shifted from the pivotal connection at I26 to the lever cam I30.

As long as force is applied to the end I38 of the lever, the valve stem I34 remains displaced and the cam I30 moves relative to the stem until the lever comes to the end of its counterclockwise travel as determined by the beveled end I40 of the opening I28. The shifting of the axis of the lever and the movement of the cam relative to the valve stem is brought about by the piston I I0 being moved to the right by the released pressure fluid flowing into the piston chamber I08 and this movement is so correlated that the pissired, the force of the operator is removed fromthe lever at the end of such desired movement.

This relieves the pressure being exerted by the lever cam on the valve stem I34, whereupon the valve will seat, halting fluid flow and consequent- Unseating this latter valve connects the control unit ports 92 and 84, permitting flow of fluid therebetween. As soon as the pressure is relieved in the line 56 and the valve stem I32 is depressed, the pressure in the line I8 acting on the right side of the operating unit piston. 62 will force the piston to the left. This forces the fluid on the left side of the piston back into the line 36 which'in turn forces the pistons I I0 in the control units 26 t0 the left, moving the fluid in line 56 into line 50,- through the ball valve and into return line 40, thence back to the reservoir I2. Of course, if

described may be visualized in Figure 1 by delet ton will contact the end wall of the chamber I02 ing the pressure line 22, the return line 40, and

v the lines 34 and 48 interconnecting the units 26;

then an additional line should be placed to connect the port I00 of the right-hand unit 26 directly with the third side of the T which connects lines 46 and 44. When two or'more operating 3 units are provided in the system these units are 1y movement of the piston H0, the piston being retained at the point at which it was thus halted.

Conversely, if the lever I24 is moved in a clockwise direction about the pivotal connection I28,

the valve stem I32 is displaced'unseating its respective valve I36 and allowing fluid flow from the control pressure line 44 through port 94, past the valve and into return line 38 via port 92. As this flow is permitted, pressure is released from the left side of piston H0 and consequently from the left side of the operating unit piston head 64, and the pressure on the right or smaller side of piston head 64 plus the power of the spring 86 will move piston head 64' and piston I I0 to the left whereupon the action of the lever cam and the valve stem I32 will be identical to that described for counterclockwise movement, the cam being removed from contact with the valve by the leftward movement of the piston. I

1 manner and degree as the one actuated by the operator. For example, if the left unit 26 is being operated by moving the lever I24 in a counterclockwise direction, fluid will be released from pressure line 22 and will enter the piston chamber I08 via the ball valve I36 and. lines 54, 56. This fluid will then force the piston IIO to move to the right, displacing the fluid in piston chamber I02 into the line 34 and consequently into the piston chamber I08 of the right control unit 26. The piston IIO of the right unit will thus be moved to the right causing the lever I24 of the right unit to assume the same relative position as the lever I24 of the unit being operated. Conversely, if the lever I24 of left unit 26 is moved in a clockwise direction, pressure of the cam I will be relieved from the valve stem I34, permitting the pressure in line 22 to seat the ball valve I36 and thus seal itself from entering line 54. Then, as the lever I24 is moved further clockwise, the cam I30 will contact and depress the valve stem I32, unseating its respective ball valve.

connected in parallel, in which case branch lines from the control unit piston port 90 would connect to the port 80 of each operating unit. Likewise branch lines from the pressure line I8 would connect to the port I8 of each unit.

I In the event of failure in the pressure system 'at any location other than between the control unit piston chamber- I02 and the left side of the operating unit piston head 64, the units may be operated manually by the control lever I24 through a closed system. As the lever is moved counterclockwise, the fluid is forced from chamber I02 into the operating unit thus moving the piston head 64 to the right end of its travel against the power of the spring 86. Conversely, as the lever is moved clockwise, a suction'is cre- 1 ated by the piston head 2 which draws fluid from the operating unit, and the spring, in addition to the suction force, moves the piston head 64 to the left end of its travel.

The double acting floating piston check valve 32 is located in the pressure line I8 near the operating unit and comprises a housing I42 with valve type seats I44 at opposite ends thereof. A piston I46 is movable from one end of the housing to the other depending upon the direction of fluid flow and is adapted to seat at either end thus shutting off the flow of fluid. The length of the housing is such that a full stroke of the operating unit piston is allowed in either direction before the piston I46 of the check valve seats at either end of the housing. This valve is provided to allow full stroke of the operating unit piston during manual operation through a closed system and also to prevent complete fluid leak.- age under certain conditions in event of damage tothe system. For example, ifJa break should occur in the line I8 on the right hand side of the valve, the only fluid lost would be that between the valve and the right hand side of the operating unit 62 by reason of the fact that the fluid on the left side of the valve would move the piston I46 of the valve to the right,.forcing it to seat and retain the pressure. in the main pressure supply line I6. On the other hand, if the break should occur in the main pressure supply line I8 or in the portion of the line I8 which conton lnthat both valves in the piston no nects the valve 32 to line I6, the valve piston m would move to the left and seat, thus preventing leakage at that point. In this way the valve 7 '32 would cooperate with the valve 30' to maintainfluid in and between the units proper for opera- .tion through a manual closed system.

The successful operation of the embodiment just described is based upon the difference in displacement. areas of the operating unit piston head. As at present preferred, the area on the left side of the piston head is twice the area on the right side. In this way a common pressure value may work against itself because the pressure on the larger displacement side will overcome the pressure on the smaller displacement side while the pressure on the smaller side is still ample to move the piston when the pressure on the larger side is relieved. When the units are being operated manually through a closed system and no constant pressure supply is available the smaller side of the operating unit piston will not be' pressure loaded other than by the spring and this is easily overcome by the fluid force applied manually from the control lever.

The irreversibility of my-system is obtained through the closed system feature which feature effectively prevents movement of the operating unit piston by vibration or other external forces regardless of-whether the system isbeing operated manually or by pressure, and, while af- .fording irreversibility, the ease of control from any number of control units which may be included in the system is unimpaired. This is due to the fact that it is impossible to displace the ,control unit valves other than by a back pressure greater than the pressure supply, or by the control lever proper. In the event that a force greater than the pressure supply should be exerted on the operating unit piston to move the piston leftward and cause a back pressure to displace the valve I36 between control unit ports 86-88, the check valve would be closed by the back pressure and prevent any fluid movement, consequently preventing any movement of the operating unit piston. Rightward movement of the piston is prevented by the, pressure output of the pump 6 acting on the small displacement side of the piston.

I The manual type position indicating feature of my invention is made possible because the stroke of the control unit piston and the stroke of the operating unit piston are substantially equal. In I other words the operating unit piston will reach the end of its rightward or leftward travel simultaneously with the termination of a corresponding travel of the control unit piston. The control lever, being pivotally connected to the control unit piston, then naturally indicates the.

gained;

In an alternate embodiment,'as depicted by Figure 4,- my system may be utilized for operating elements requiring more "actuating force thanis obtainable from the embodiment first described. In this alternate system,the control unit 281s employed as before and the operating unit 24 is of identical design but is larger, say

double the size of the unit used in Figure 1; the fluid lines being so rearranged that operation of the control unit piston acts directly upon the right or lesser displacement side of the operating unit piston rather than upon the left or larger displacement side, The rearrangement of the fluid lines is necessary in order to obtain efllcient operation with the double size unit 24 and also to obtain the indication feature. This may be readily understood because if the double size unit were incorporated in the system of Figure l the displacement of the control unit piston would be only half the amount required to displace the operating unit piston through a full stroke. In such case, the control unit piston would reach the end of its travel at the time the operating unit piston had completed only half of its travel. The control unit piston valves II8 would then have to open in order for sufficient fluid to be metered through the piston to complete the travel of the operating unit piston. In other words, there would always be a lag between the operation of the control unit and the operating unit, and correct indication of the position of the operating unit piston would not be had on the control lever I24. To obtain the desired coordination and, consequently, indication between the control unit and the larger operating unit, the rearranged system is utilized wherein the supply pressure line I6 is branched into lines I58-I52.

Line I50,connects to the port 98 of the upper left control unit valve, and line I52 connects to the port 90 of the control unit piston chamber I82. The control unit piston chamber I88 is connected through port I00, by a line I54, to the operating unit port I8 opening to the lesser displacement side of the piston head 84. The chamber on the left end of piston head 64 is connected through port 80, by a line I56, to the port 98 of the upper left'control unit valve, and a line I58, teed into line I56, connects into port 94 of the upper right control unit valve. The return line 42, leading to the reservoir I2, is connected at port 82 to the upper right control unit valve.

Operation of'thisembodiment is similar in many respects to the embodiment first described.

Pressure fluid, being available at port 88, is released when'the control unit lever I24 is moved counterclockwise, depressing the valve stem I24. Thefluid then flows through line I56 to the left end of operating unit piston head 8 moving the piston to the right and extending the rod 62. This rightward movement forces fluid from the right end of the operating unit, through line I54,

and moves the control unit piston IIII to the right, which in turn forces fluid on the right side of the control unitpiston back into the line I8 via the line I52. The action of the lever I24 and the valve stems I20 of the control unit piston is the same as previously described. When the control lever I24 is moved clockwise, the upper right control unit valve is opened permitting fluid to flow from line I58 through line I58 and thence into return line-42 which opens the system and allows pressure fluid from line I52 to enter port and move the control unit piston leftward consequently forcing the operating unit piston leftward, retracting the piston rod.

The additional power of this system is obtained through valving the pressure fluid directly to the greater displacement side of the larger operating unit and through utilizing the displacement of the control unit piston to force pressure fluid to the right side of thepperating unit.

Still other methods of increasing the power of systems using the principle of my units will be obvious to those skilled in the art, after understanding the invention, and while the invention has herein been described in its present preferred embodiments, various changes and modifications may be made therein without departing from the spirit and the scope thereof. It is aimed in the appended claims to cover all such modifications and changes.

I claim:

1. In a hydraulic control unit, a piston chamber, a piston adapted to reciprocate in said chamber, a pair of poppet valves, and a control lever, said lever being pivotally connected to said piston and having a cam situated above said piston and in the horizontal plane of said poppet valves, said cam being; adapted to unseat either of said valves, each of said valves having. two ports which are interconnected when their respective valve is unseated, and the said piston chamber having a port at each end thereof for fluid to enter and exit therefrom and reciprocate said piston in response to operation of said valves by said control lever, said ,piston having a passage'therethrough, a poppet valve being provided at each end of said passage and adapted to close said passage against fluid flow, each of said valves checking fluid flow in opposite directions, whereby fluid flowing in one side of said piston chamber confronts said piston, moving same and unseating the valve in the confronted end, fluid then entering said piston passage where it is retained until said piston reaches the end of its stroke whereupon the valve in the other end of said piston is unseated by contact with the end of said piston chamber. I

2. In a remote control pressure system, a unit adapted to control the flow of fluid pressure therein, a piston in said unit adapted to force fluid through said system, a first valve means in said unit for admitting pressure to one side of said piston to move said piston in one direction, a second valve means co-planar with said prst valve means for releiving pressure on said side of said piston to permit said piston to return, an operator actuated single lever. carried by said piston for movement therewith, said lever lying in a plane transverse to saidvalve plane andbeing adapted to individually open and close either of .said valves to control pressure movement of said piston and to move said piston manually in the absence of pressure supply, and additional valve means in said piston for by-passing hy-.

draulic pressure through said piston in the direction of 'piston movement when said piston reaches the end of its stroke.

3. In a remote control pressure system, a unit therein, said unit including a piston adapted to.

force fluid through said system,-multiple valve means for admitting pressure to move said piston, a single lever pivotally carried by said piston, means integral with said lever for individually contacting and operating said multiple valve,

means, said single lever rotating about said piv--' and additional valve means'in said piston for bypassing hydraulic pressure through said piston in the direction of piston movement. when said piston reaches the end of its stroke.

5. In a remote control pressure system, a'unit adapted to control the flow of fluid pressure therein, said unit including a housing having aplurality of valve chambers and a plurality of piston chambers, a valve in each of said valve adapted to control the flow of fluid pressure therein, said unit including a pair of valves, a

control lever, a cam on said lever, said cam being adapted to contact and open either one or the other of said valves in response to movement of said lever, a piston adapted to be moved by pressure when either of said-valves is open and to be rection of piston movement when 'said' piston reaches the end of it stroke.

4. In a remote control pressure system, a unit adapted to control the flow of fluid pressurechambers, a piston, a piston head movable in each of said piston chambers and fixed to said piston, a control lever carried by said piston for individually opening said valves to admit pressure to and release pressure from said piston and efiect movement thereof and adapted to close said valves whereby said flow of fluid pressure and said piston movement are halted, and additional valve means in said piston for by-passing hydraulic pressure through said piston in the direction of piston movement when said piston reaches the end of its stroke as defined by said piston chambers.

6. In a remote control pressure system, a unit adapted to control the flow of fluid pressure therein, said unit including a housing having a plurality of valve chambers and a plurality of piston chambers, a valve in each of said valve chambers, a piston, a piston head movable in each of said piston chambers and fixed to said .piston, a control lever carried by said piston bepiston and to effect movement of said piston manually by'said lever in the absence of fluid pressure, and additional valve means in said piston for by-passing hydraulic pressure through said piston in the direction of piston movement when said piston reaches the end of its stroke as defined by said'piston chambers.

7. In a hydraulic control unit, a piston chamber, a piston adapted to reciprocate in said chamber, valve means'for admitting hydraulic pressure to reciprocate saidpiston, a lever carried by said piston for operating said valve means and for moving said piston manually in the absence of hydraulic pressure, said lever being directly pivoted to said piston, and additional valve means in said piston for by-passing hydraulic pressure through said piston in the direction of piston movement when said piston reaches the end of its stroke as defined by said piston chamber.

8. In a control unit, a pair of valve chambers, a valve in each of said chambers, a pressure-in port on one side of one of said valves, a pressureout port on the other side of said valve, a returnin port on one side of the other valve, a returnout port on the other side of said last named valve, an operating stern for each of said valves direct pivotal connection between said valve operating lever and said piston, and an additional valve means in said piston-for lay-passing pressure through said piston in the direction of piston movement when said piston reaches the end 8 of "its stroke.

ORVILLE A. WHEELON. 

